B&W 803D vs 803Di

The 803Di is overall the better loudspeaker as you would hope (and expect) for a newer version. But it is not a dramatic improvement - move akin to a BMW mid-life automobile face-lift where the engine has been upgraded and and a few cosmetic exterior changes applied. The only cosmetic update I really appreciate is the magnetically attached grille - makes it easy to remove for serious listening.

The 803Di is marginally more detailed in midrange and treble, and has a tighter and more articulate bass. The 803D midrange and treble are better matched in sensitivity whereas the 803 Diamond treble balance sounds slightly tilted up.

Overall I think the 803D is better balanced tonally for relaxed listening whereas the 803Diamond is a touch more upfront and rewards more focused listening sessions.

The 803 Diamond is overall the better loudspeaker as you would hope (and expect) for a newer version. But it is not a dramatic improvement - move akin to a BMW mid-life automobile face-lift where the engine has been upgraded and and a few cosmetic exterior changes applied. The only cosmetic update I really appreciate is the magnetically attached grille - makes it easy to remove for serious listening.

The 803 Diamond is marginally more detailed in midrange and treble, and has a tighter and more articulate bass. The 803D midrange and treble are better matched in sensitivity whereas the 803 Diamond treble balance sounds slightly tilted up.

Overall I think the 803D is better balanced tonally for relaxed listening whereas the 803 Diamond is a touch more upfront and rewards more focused listening sessions.

Is it worth the extra money? Depends on the cost differential and how far you will go with your front-end electronics. The 803 Diamond will definitely reward better front-end electronics - e.g. the difference between my two SACD players is that more obvious, although both are still enjoyable to listen to.

Thanks, Mark_nz. Given your answer, how would you adjust it if these were to be geared more for theater experience rather than music? Say, 90% movies, 10% music.

Assuming other considerations are equal (age, condition, finish preference etc), then for movies I think the savings will be better rewarded by upgrading the AV and projector.
The 803D/HTM2D is more than good enough for movies. However if you really very picky about voice quality, the 803/HTM2 Diamond may be sway your choice - recommend you compare the HTM2D and HTM2 Diamond.
Also for background music the 803D is very good; most of the improvements for the 803 Diamond will only be appreciated when listening in the sweet spot.

If you can go and have a listen. The newer range is vastly superior in my opinion.